The three primary approaches used to clean commercial and residential carpets are steam or hot water, foam and dry systems. Dry-type carpet cleaning systems are further divided into two broad categories. One uses a dry or substantially dry powder and the other uses granules, each of which is several times larger than a powder grain. The granules are slightly moistened with cleaning solvents for dirt removal. The inventive machine has utility for both categories of dry systems cleaning solvents for dirt removal. The inventive machine has utility for both categories of dry systems but relates primarily to those using granules rather than powder. Such machine also has utility in situations where only carpet vacuuming is performed. That is, its long-bristled brushes are highly effective in removing loose sand and other soil not requiring the application of solvent-bearing material.
Of the dry granular carpet cleaning systems, the best known and most widely used is the HOST.RTM. dry extraction system offered by Racine Industries, Inc. of Racine, Wis. The HOST.RTM. system applies granules to carpet fibers using a machine as shown in Rench et al. U.S. Pat. Nos. 2,842,788 and 2,961,673. Such machine, sold under the HOST.RTM. trademark, is devoid of vacuum capability and has a pair of spaced brushes counter-rotating at relatively low speed (about 350 rpm) to stroke the cleaning granules into, through and across the carpet and its fibers.
The granules are referred to as "dry" and are substantially so even though moistened with cleaning solvents. When stroked as described, these granules "scrub" dirt and soil from such fibers including oily and non-oily soil. The carpet is cleaned by working the HOST.RTM. machine across it in different directions and during such cleaning process, granules migrate to the carpet backing adjacent to the base of the fiber. A few granules also adhere lightly to the fibers along their lengths. Heretofore, conventional carpet vacuum machines have been used for removing these dirt-ladened granules.
S. C. Johnson Co. of Racine, Wis. sells a vacuum cleaning machine known as VECTRON.TM.. The machine can be used for hand vacuuming using a wand. However, one must take the entire machine to the site to do so. It is believed that such machine is based upon one or both of the following U.S. Pat. Nos. 5,643,748; 4,853,008 (Dyson).
The invention involves improvements in the HOST.RTM. machine depicted in the aforementioned Rench et al. patents and in updated versions of such machine. However, after analyzing this specification, it will be apparent as to how other carpet cleaning machines can benefit from such improvements.
A feature of the known HOST.RTM. machine is that the handle (which usually requires two hands to attach and detach) can be latched in an upright position. Such handle is free to "articulate" or swing continuously through an arc of about 180.degree. after the latch is released. While such handle arrangement has been highly satisfactory, it does require that the operator be the motive force urging the machine (with its counter-revolving brushes) forward and rearward as the carpet is brushed clean by the HOST.RTM. granules. In other words, the known handle arrangement permits little, if any, degree of self-propulsion as set forth in the detailed description of the invention.
Another aspect of the known HOST.RTM. machine is that when it is equipped with a removable, handle-mounted vacuum pod (an innovation mentioned in greater detail below), the operator is required to support the weight of such pod when grasping the handle during machine use. This is tiring and requires additional effort made unnecessary by the invention. And in some types of carpet cleaning machines (e.g., the VECTRON.TM. machine mentioned above which brushes a dry powder into the carpet and then remove such powder by vacuuming) the vacuum unit is not separable from the machine.
The HOST.RTM. machine is available with four different brushes having varying degrees of bristle rigidity, namely, stiff, standard, moderately soft and soft. Soft brushes are for use on Saxony, Plush and Berber style carpets which are more often installed in residences rather than in commercial applications. When equipped with brushes having soft bristles, the bristles often bend excessively and the machine tends to "wallow," "yaw" or "skew." That is, it tilts generally sideways in some undesirable attitude as the machine is manipulated.
This can cause an edge of the shroud (which is positioned above the brushes) to catch or snag on the carpet and the carpet may thereby be damaged. And when the machine is pushed forward or pulled rearward too rapidly or when the handle is "torqued" (twisted about its long axis), the soft bristle brush can partially collapse. When a vacuum pod is mounted on the handle, the extra weight can cause machine wallowing when using either the soft or moderately soft brushes.
In the known HOST.RTM. machine, the "free swinging" handle arrangement makes it difficult for the machine operator to most effectively manipulate the machine angularly or laterally back and forth across the carpet. Such manipulation is sometimes desired or even required when making several passes over a more dirt-laden portion of such carpet.
Improvements overcoming the aforementioned disadvantages would be important advances in the art.